This invention is particularly applicable, for example, to an integral fuel line comprised of three concentrically mounted tubes in which the high pressure line is made to be the innermost tube, the low pressure or return line defining an intermediate tube is spaced from and surrounds the innermost tube, and the vapor recovery line defining an outer tube is spaced from and surrounds the intermediate tube. In a fuel distribution system of the fuel injection type for a motor vehicle, the high pressure line is used to deliver gasoline from a fuel storage tank at the rear of the motor vehicle to multi-port injectors at the front of the motor vehicle for subsequent distribution to various cylinders of the vehicle's engine. The return line is located adjacent the ejectors for returning excess or unused portion of the gasoline back to the fuel tank. The vapor recovery line is used to collect vaporized and evaporated gasoline from the "canister" area and other points adjacent the vehicle's engine and to return the same back to the fuel storage tank. Further, a manifold or coupling member (that is, a terminal block) is typically connected to each end of the integral fuel line.
Such a prior art integral fuel line with associated terminal blocks connected to its ends is described and illustrated in U.S. Pat. No. 5,076,242, which is assigned to the same assignee as the present invention. The '242 patent is hereby incorporated by reference. As shown in FIG. 3 of the '242 patent, the terminal block 22 is provided with a high pressure coupling union 44 surrounding a passage 43, a low pressure coupling union 50 surrounding a passage 48, and a vapor recovery coupling union 56 surrounding a passage 54. The respective innermost tube 30, intermediate tube 34 and outer tube 38 of the integral fuel line are joined to the corresponding coupling unions 44, 48, and 56 of the terminal block 22 by an adhesive such as glue. It has been found that the use of an adhesive is sometimes less than satisfactory as the means for securing the tubes to the coupling unions in the terminal block. Generally, the adhesives used are not chemically resistant to the gasoline and will eventually become dissolved. As a result, the union of the tubes and the coupling unions in the terminal blocks will be destroyed and a costly repair and/or replacement of the fuel line is required.
It would therefore be desirable to provide an improved connector structure for securely connecting a concentric fuel line having a plurality of tubes to a manifold having corresponding fluid passages in communication with the plurality of tubes. Further, it would be expedient that the connector structure provides for mechanically and positively connecting each of the plurality of tubes and the corresponding fluid passages within the manifold after the fuel line is attached to the manifold.